Don’t give up, Anna! We’re here to help 
Putting aside Jake’s particular notebook and the associated licensing restrictions (thanks @Fabian), if you are willing to use Observable’s opensource runtime, you may download the code for any notebook and run it offline (provided the notebook doesn’t further require other online resources). The official guide to achieving this is here:
You also often can search this forum to find other elaborations, such as my more detailed response here.
Let us know if this gets you closer 
Of course, if you wish to recreate the visualization without using Observable’s open source reactive runtime, there are several more steps. It’s not always easy to convert a notebook into ‘vanilla’ JavaScript, but there are several other posts on this forum that help to provide insights into this prcess.
Cheers!